Ten-year-old Francisco Steib rarely sits through an entire dinner at home. There's still food on everyone's plate when he starts to get fidgety and has to get up.

Francisco, a Lakeview resident who was diagnosed with attention deficit hyperactivity disorder 31/2 years ago, will walk around the table, move to another chair or at the very least stand by his seat, said his mother, Maggi Steib.

"For some people, that's a real challenge," Steib said. "They want their kids to be able to sit still, but he really cannot sit still. … He doesn't have control over it, and you as parents don't have control over it."

Two recent studies completed by one of the nation's largest not-for-profit health plans offer insight into ADHD, the cause of Francisco's difficulties and one of the most common neurobehavioral disorders of childhood.

Offering a piece of the puzzle why certain children get ADHD, the first Kaiser Permanente study reveals an association between the disorder and health complications that cause oxygen deprivation before birth. The second study suggests a rise in the rate of children being diagnosed with ADHD.

"We want to prevent even one adverse outcome," said Dr. Darios Getahun, researcher with the Kaiser Permanente Southern California Department of Research & Evaluation and lead author of the studies.

ADHD is defined as a cluster of two sets of symptoms, experts said. Some children with the disorder show signs of hyperactivity or impulsivity, such as fidgeting or moving excessively, interrupting conversations or grabbing items from others. Others suffer from inattention, such as difficulty following instructions or forgetfulness. Some have both types of symptoms.

"When we see kids clinically who have had ADHD for many years, everyone has been suffering," said Dr. Mina Dulcan, head of Child and Adolescent Psychiatry at Ann & Robert H. Lurie Children's Hospital of Chicago. "One of the things people don't remember is kids and families with ADHD suffer. It's a real thing."

It's well known that the cause of ADHD is strongly genetic but also linked to brain development, experts said. While previous studies have shown that in-utero exposure to ischemic-hypoxic conditions — complications that deprive the brain of oxygen — often lead to brain injury and developmental problems, Kaiser Permanente's study published in Pediatrics journal shows children who experience prenatal IHCs have a 16 percent greater chance overall of developing ADHD.

The problem is that IHCs, such as birth asphyxia, neonatal respiratory distress syndrome and preeclampsia, can compromise the levels of oxygen and nutrients transported from the mother's blood to the fetus while the child's organs are still developing, according to the study.

Children born breech or transverse (shoulder first) or whose deliveries involved cord complications had a 13 percent increased risk of ADHD, according to the study, which involved analyzing the health records of almost 82,000 children ages 5 to 11.

Compared with children who were not exposed, those who experienced birth asphyxia, preeclampsia and neonatal respiratory distress syndrome faced a 26 percent, 34 percent and 47 percent greater risk, respectively, of developing ADHD, according to the study. The strongest connection was found in preterm births.

One benefit of this study is that it could help identify at-risk children earlier.

If treated at a younger age, "they will do better in school and socially," Getahun said. "That is very important."

Some experts, however, question whether putting the parents of children who suffered from IHCs on guard for ADHD truly is beneficial.

The disorder is easiest to diagnose around age 7, said Mark Stein, University of Illinois at Chicago professor of psychiatry and pediatrics and director of the Hyperactivity, Attention and Learning Problems Program. The further a child is from that age, whether it's older or younger, the more difficult the disorder is to diagnose.

All 2-year-olds have ADHD symptoms, he said. Sometimes those symptoms are nothing, and sometimes they are indicators of a more severe problem that might be overlooked if ADHD is assumed. In addition, medications used to treat ADHD don't work as well in younger children.

"I think it's important to be careful in diagnosing it, especially in younger children," Stein said.

In addition, parents should keep in mind that IHCs don't account for the large majority of cases of ADHD, Stein said.